Cationic iridium(III) complexes bearing ancillary 2,5-dipyridyl(pyrazine) (2,5-dpp) and 2,2 ':5 ',2 ''-terpyridine (2,5-tpy) ligands: synthesis, optoelectronic characterization and light-emitting electrochemical cells

Kamrul Hasan, Loic Donato, Yulong Shen, Jason D. Slinker*, Eli Zysman-Colman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)

Abstract

Four cationic iridium(III) complexes of the form [Ir(C^N)2(N^N)]+ bearing either a 2,5-dipyridylpyrazine (2,5-dpp) or a 2,2′:5′,2′′-terpyridine (2,5-tpy) ancillary ligand and either 2-phenylpyridine (ppy) or a 2-(2,4-difluorophenyl)-5-methylpyridine (dFMeppy) cyclometalating ligands were synthesized. The optoelectronic properties of all complexes have been fully characterized by UV-visible absorption, cyclic voltammetry and emission spectroscopy. The conclusions drawn from these studies have been corroborated by DFT and TDDFT calculations. The four complexes were assessed as emitters in light-emitting electrochemical cells. Complex 1a, [Ir(ppy)2(2,5-dpp)]PF6, was found to be a deep red emitter (666 nm) both in acetonitrile solution and in the electroluminescent device. Complex 2a, [Ir(ppy)2(2,5-tpy)]PF6 was found to be an orange emitter (604 nm) both in solution and in the LEEC. LEECs incorporating both of these complexes were stable over the course of around 4–6 hours. Complex 1b, [Ir(dFMeppy)2(2,5-dpp)]PF6, was also determined to emit in the orange (605 nm) but with a photoluminescent quantum yield (ΦPL) double that of 2a. Complex 2b, [Ir(dFMeppy)2(2,5-tpy)]PF6 is an extremely bright green emitter (544 nm, 93%). All four complexes exhibited quasireversible electrochemistry and all four complexes phosphoresce from a mixed charge-transfer excited state.

Original languageEnglish
Pages (from-to)13672-13682
Number of pages11
JournalDalton Transactions
Volume43
Issue number36
Early online date28 Jul 2014
DOIs
Publication statusPublished - 28 Sept 2014

Keywords

  • Molecular-orbital methods
  • Extended basis-sets
  • Valence basis-sets
  • Compact effective potentials
  • Transition-metal-complexes
  • Density-functional theory
  • Excited-state properties
  • Exponent basis-sets
  • Gaussian-type basis
  • Photophysical properties

Fingerprint

Dive into the research topics of 'Cationic iridium(III) complexes bearing ancillary 2,5-dipyridyl(pyrazine) (2,5-dpp) and 2,2 ':5 ',2 ''-terpyridine (2,5-tpy) ligands: synthesis, optoelectronic characterization and light-emitting electrochemical cells'. Together they form a unique fingerprint.

Cite this